Tyres wear out so quickly that I find them fun experimenting with and purchasing something different each time round. I don’t swap and change on my main bike – although I do a bit for racing on my race bike.
I will usually get a new set when the rear is worn out, which leaves the front with a bit of life left which I then keep as a spare and which often gets used.
Always go more grip up front. If swapping just one tyre move the front to the back. I usually get matching pairs but I’ve started experiementing with less grip at the rear with good success.
Main failing point of tyres for me traditionally has been how well they protect against pinch punctures. Rarely stress about ‘grip’, I think it’s more technique if I’m falling off.
Now gone tubeless and never want to go back to tubes.